Inventor: Benjamin Franklin

The lightning rod was invented by Benjamin Franklin in the early 1750’s. During this time he had been studying the similarities between electricity and lightning which he explained in letters to Peter Collinson, a friend of his in London. He began thinking that if lightning was just a large electric discharge, then it might be possible to use current knowledge about electricity to prevent damage to buildings, ships, etc. He described his lightning rod as a pointed metal pole that extended above a structure and was driven several feet into the ground. In the event of a thunder storm the pole would either dissipate the charge slowly through the point, or if it was struck, would conduct the current though the metal and away from the rest of the structure.

Benjamin Franklin decided to test his theory about lightning in 1752. Instead of waiting for a tall steeple to be built, he decided that a kite could be used instead. His famous kite experiment is now widely known. In this experiment he was able to draw sparks from a key fastened at the end of the kite string, proving that lightning and electricity were the same. He was very lucky that his kite was not actually struck by lightning, for two other scientists were killed while trying to reproduce his experiment.

After this, Benjamin Franklin’s lightning rods were placed on many important buildings in both America and Europe. There was, however, a difference between them. All of the European lightning rods had blunt points due to the belief that rods with sharp points attracted lightning more. Benjamin Franklin promoted the use of pointed rods in America, however, because he believed that rods with sharper tips worked better.

Picture from:
"Science @ Morrisville". 30 Dec. 2003 <http://morrisvillees.wcpss.net/science/science_homepage.htm>

Sources:

Bigelow, John. "Benjamin Franklin Experiments with Electricity". International History Project. 1 Jan. 2004. <http://ragz-international.com/benjamin_franklin_experiments_wi.htm>

• This is a collection of first-hand and second-hand accounts of Benjamin Franklin’s experiments with electricity.

Sahlman, Rachel. "Benjamin Franklin". Spectrum. 1 Jan. 2004. <http://www.incwell.com/Biographies/Franklin.html>

• This is a biography of Benjamin Franklin.

"The Lightning Rod". The Franklin Institute Online. 2 Jan. 2004. <http://www.fi.edu/pieces/hongell/>

• This is a description of the invention of the lightning rod.